Intel may be the biggest name in Pentium 4 chipsets, but both SiS and VIA have been steadily carving their own space and have made quite a name for themselves. The SiS 645DX is one of the most popular choices for a high-end gaming box, and also provides one of the best platforms for high-end overclocking. Due to the lack of a Pentium 4 license, VIA Technologies and their previous P4X333 hasn't been as successful as SiS, but both companies are looking for even more production from their current line of chipsets. These products are the SiS 648 and VIA P4X400, which are two powerful DDR platforms that look to provide the perfect base for a high-end Pentium 4 system.
Both chipsets have cutting-edge features such as AGP 8X, DDR333 (DDR400 unofficial support), ATA-133, and USB 2.0, in addition to the standard support for 400 and 533 MHz Pentium 4/Celeron processors. In terms of extra features, the SiS 648 includes the 963 Southbridge with integrated IEEE 1394 Firewire and a MuTIOL bus between the SiS 648 and 963 with a full 1 GB/sec. of bandwidth. The VIA VT8235 Southbridge is also a powerful, feature-rich chip, but just a tad behind the SiS 963 in most counts.
Please consult the following chipset design images for a closer look at the SiS648 and VIA P4X400 schematics and features:
The main benefit of the SiS 648 and VIA P4X400 chipsets is the ability to run at DDR400 speeds, utilize AGP 8X features and upgradeability, as well as making potential Pentium 4 overclocking and tweaking a much easier job. These are really the latest evolution of the SiS 645DX and VIA P4X333 with a greater number of features and higher performance. To give a better idea of the available crop of motherboards, we've assembled six of the very best. These include five SiS 648 boards, but since the VIA P4X400 is much less prevalent in the marketplace, we only have a single representative from Soyo in this roundup. Here is a list of the SiS 648 and VIA P4X400 motherboards we will be reviewing:
AOpen AX45-8X Max
MSI 648 MAX
Soyo P4X400 DRAGON Ultra
In this roundup, we will start off with a short review of each board, covering off features, layout, installation and BIOS options, then start on a full system and game benchmarking comparison, a FSB overclocking match up, and finish up with our Top 3 motherboard recommendations.